This invention relates to an in-tank type vehicular fuel supplying apparatus which is mounted from the bottom wall of a fuel tank.
FIG. 7 illustrates a conventional vehicular fuel supplying apparatus disclosed in Japanese Patent Laid-Open No. 1-37178, in which the fuel supplying apparatus is mounted to the bottom wall of a fuel tank and is positioned within the fuel tank.
In the figure, the reference numeral 1 is a fuel tank, of which bottom wall has formed therein an opening 2. 3 is a packing disposed around the opening 2, 4 is a set plate oil-tightly attached to the opening 2 through the packing 3. 5 is a sub tank secured to the tank inner surface of the set plate 4, and an in-tank type fuel pump 7 is mounted to a pump holder 6 secured to the inner bottom surface of the sub tank 5. 8 is a filter disposed at the suction port 7b of the fuel pump 7. 10 is a supply pipe connected through a rubber hose 9 to a discharge port 7a of the fuel pump 7, the supply pipe 10 being bent into a substantially U-shape and oil-tightly connected and extending through the set plate 4 and being connected to a vehicular body pipe 16 directed to an engine by means of a joint 14. 11 is a power line to the fuel pump 7, which extends from the power supply terminal 13 to a connector 12 oil-tightly connected through the set plate 4.
The operation of the conventional vehicular fuel supply apparatus will now be described.
By driving the fuel pump 7 by a voltage applied from the power supply terminal 13 through the connector 12 and the power supply line 11, the fuel 15 in the fuel tank 1 is sucked through the filter 8 and pressurized by the fuel pump 7 and supplied to the vehicle body side pipe 16 directed to the engine through the supply pipe 10.
In the above-described conventional vehicular fuel supply apparatus, when the vehicle body side pipe 16 is disconnected from the joint 14 of the supply pipe 10 for the vehicle body maintenance or the like, a jet of the fuel 15 from the supply pipe 10 is generated due to the head pressure H of the fuel 15 within the fuel tank 1 and pressure P inside of the fuel tank 1, causing the fuel to out and scatter to disadvantageously degrade the maintenance working efficiency.
In order to cope with this problem, another conventional vehicular fuel supplying apparatus as shown in FIG. 8 has been proposed in which a fuel cock 18 is installed in the midway of the supply pipe 10 at the position under the set plate 4 so that the fuel cock 18 may be closed when the fuel supply pipe 10a is to be disconnected from the vehicular body side pipe 16. However, because the added fuel cock 18 must be manually operated, the fuel pump 7 may sometimes be driven with the fuel cock 18 inadvertently left closed after the supply pipe 10a has been reassembled to the vehicular body side pipe 16, generating an abnormal pressure rise within the supply pipe 10 which may cause a failure of the fuel pump 7.